Efforts to improve PV devices, particularly those devices that are integrated into building structures (e.g. roofing shingles or exterior wall coverings), to be used successfully, should satisfy a number of criteria. The PV device should be durable (e.g. long lasting, sealed against moisture and other environmental conditions) and protected from mechanical abuse over the desired lifetime of the product, preferably at least 10 years, more preferably at least 25 years. The device should be easily installed (e.g. installation similar to conventional roofing shingles or exterior wall coverings) or replaced (e.g. if damaged). It may be desirable to provide a means of electrically connecting individual PV devices to one another and then to the balance of the system (BOS). Additionally, the PV device should transmit, at least on the front surface, UV and visible light without degrading the material of the front surface layer.
To make this full package desirable to the consumer, and to gain wide acceptance in the marketplace, the system should be inexpensive to build and install. This may help facilitate lower generated cost of energy, making PV technology more competitive relative to other means of generating electricity.
PV devices are commercially available today but they suffer from one or more deficiencies. In some cases, particularly in roof applications, multiple roof penetrations may have to be made, resulting in the roof which may have to be subsequently sealed against leaks. In other instances, extensive wiring may be required to connect the PV system together. The roof penetrations and/or extensive wiring can make installation time consuming and expensive.
Also, current PV devices may also include functional deficiencies due to their methods of construction. Laminated PV devices that do not have encapsulated edges may present mechanical and environmental challenges for the laminate. PV devices with secondary perimeter edges may address this problem, but, due to the resulting thickness changes at the edge from this same protecting addition, can be susceptible to fouling from dust, moisture, and other materials.
Existing art fastening systems for PV devices may allow for the device to be directly mounted to the building structure or they may fasten the devices to battens, channels or “rails” (“stand-offs”) above the building exterior (e.g. roof deck or exterior cladding). These systems may be complicated, typically do not install like conventional cladding materials (e.g. roofing shingles or siding) and, as a consequence, may be expensive to install. Also, they may not be visually appealing as they do not look like conventional building materials. “Stand-offs” to mount PV device every 2-4 feet may be required. Thus, installation cost can be as much or more than the cost of the article. For example, a primary disadvantage of this type of mounting system is that it needs to be weather protected itself. In other words, the stand-offs are externally mounted to the roofing system and penetrate it, providing a potential water leakage site. To prevent this, each stand-off must be weatherized individually which is costly, time consuming, and undependable.
Locating and/or electrical connection features are not necessarily incorporated (depends on specific prior art reference). Existing art locating features do not take into consideration the variability in most building structures, particularly in roof structures, and may not be, or are not, consistent with existing roofing materials and designs. Notwithstanding these advancements, there remains a desire to present alternative solutions for various applications.
Among the literature that may pertain to this technology include the following patent documents: U.S. Pat. Nos. 4,040,867; 4,321,416; 4,322,261; 5,575,861; 5,743,970; 5,647,915; 5,590,495; US20060225776; US20060266406; US20070084501; US 2008/0035140 A1; U.S. Pat. No. 7,328,534 B2; U.S. Pat. Nos. 4,830,038; 5,008,062; 5,164,020; 5,437,735; 7,049,803; JP-A-58021874; DE-A-2757765; EP867041; EP1744372; U.S. Provisional Application Nos. 61/050,341 (filed 5 May 2008); 61/098,941 (filed 22 Sep. 2008); 61/149,451 (filed 3 Feb. 2009), and PCT Applications filed concurrently for attorney docket Nos. 67558-WO-PCT (1062A-016WO); 67666-WO-PCT (1062A-017WO); and 68428-WO-PCT (1062A-019WO), all incorporated herein by reference for all purposes.